Air Bar with Independently Adjustable Plugs

ABSTRACT

An air bar for guiding a web is provided. The air bar includes a body having holes formed therein, a first plug inside of the body and a second plug inside of the body. The first and second plugs define a cavity inside of the body. The air bar also includes an adjusting device for selectively moving the first plug and the second plug independently of one another.

Priority to U.S. Provisional Patent Application Ser. No. 61/276,974 filed Sep. 18, 2009, is claimed, the entire disclosure of which is hereby incorporated by reference.

The present invention relates generally to post-press devices in the graphics industry and more particularly to devices for guiding webs or ribbons.

BACKGROUND OF INVENTION

U.S. Pat. No. 4,492,328 discloses a tubular turning rod formed with a row of air exits opening or holes therein. A flexible ribbon or tape, having a longitudinal slit therein, is positioned within the tube, the position of the slit being adjustable with respect to the openings in the tube.

U.S. Pat. No. 5,452,834, hereby incorporated by reference herein, discloses a turning bar for changing the direction of a web of paper exiting a printing press, comprising an axisymmetric cylindrical wall having two half surfaces, one half surface having air blow-holes distributed therealong, and means for blocking the airblow-holes.

U.S. Pat. No. 5,520,317 discloses an adjustable turning bar used in guiding and turning a web of material and, in particular, a paper web. The turning bar is connected at its ends by joints to support frames so that it can be adjusted.

A system supplied by Goss International Americas, Inc., the assignee of the present invention, includes an air bar that has two plugs that may only be adjusted simultaneously to block holes in the air bar in a symmetrical manner about a longitudinal centerline of the angle bar.

BRIEF SUMMARY OF THE INVENTION

An air bar for guiding a web is provided. The air bar includes a body having holes formed therein, a first plug inside of the body and a second plug inside of the body.

The first and second plugs define a cavity inside of the body. The air bar also includes an adjusting device for selectively moving the first plug and the second plug independently of one another.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described below by reference to the following drawings, in which:

FIGS. 1 a, 1 b, 1 c show an air bar for use in guiding webs and ribbons in post-press devices in the graphics arts industry according to an embodiment of the present invention;

FIGS. 2 a and 2 b show more detailed views of an adjusting device of the air bar shown in FIGS. 1 a, 1 b, 1 c;

FIGS. 3 and 4 show webs being turned by the air bar shown in FIGS. 1 a, 1 b, 1 c; and

FIGS. 5 a, 5 b, 5 c show a plug of the air bar shown in FIGS. 1 a, 1 b, 1 c.

DETAILED DESCRIPTION

FIGS. 1 a, 1 b, 1 c show an air bar 10 for use in guiding webs and ribbons in post-press devices in the graphics arts industry. Air bar 10 includes a body 12 that has holes 100 (FIGS. 3, 4) formed therein for forcing air from inside an internal cavity 14 of air bar 10 towards a web moving adjacent to an outer surface of body 12. Air is provided into internal cavity 14 by an air source. Internal cavity 14 is delimited by two plugs 16, 18. Internal cavity 14 may be varied by moving plugs 16, 18 with an adjusting device 11, which may include an actuator 24, a first shaft 20 and a second shaft 22. In a preferred embodiment, actuator 24 is a crank. Plugs 16, 18 are supported on respective shafts 20, 22 and include threaded holes that match threads on the outside of shafts 20, 22. Crank 24, which may be located on an axial end 30 of air bar 10, may rotate shafts 20, 22, together or independently to adjust length L and the location of internal cavity 14.

Varying the location and length L of internal cavity 14 allows air bar 10 to provide air only through holes 100 (FIGS. 3, 4) in body 12 at positions where a web is passing over of the outer surface of body 12, which may conserve the amount of air that is supplied to air bar 10. A length L of internal cavity 14 may be adjusted by moving plugs 16, 18 simultaneously towards or away from each other with adjusting device 11 to accommodate different web widths. Shafts 20, 22 are threaded in opposite directions so that if crank 24, while engaging both shafts 20, 22, is rotated in one direction, plugs 16, 18 move towards one another and decrease length L of cavity 14. If crank 24 is rotated in the opposite direction, plugs 16, 18 move away from one another and increase length L of cavity 14. For example, as shown from FIG. 1 a to FIG. 1 b, crank 24, coupled to both shafts 20, 22, may rotate shafts 20, 22 simultaneously and decrease length L of internal cavity 14 by moving plugs 16, 18 towards one another.

Plugs 16, 18 may also be adjusted independently of one another to move internal cavity 14 within body 12 or increase length L of internal cavity 14. For example, as shown from FIG. 1 a to FIG. 1 b, crank 24, coupled to shaft 20, but not shaft 22, may rotate shaft 20 independently of shaft 22 and decrease length L of cavity 14 and the position of cavity 14 within body 12, by moving plug 16 towards plug 18. Adjusting the position of internal cavity 14 within body 12 allows air bar 10 to selectively provide air to passing webs at different locations along the outer surface of body 12. Crank 24 may be held in position by a spring loaded detent lever 26. A spring 28 is provided between shafts 20, 22 to allow for assembly tolerances.

FIGS. 2 a and 2 b show more detailed views of adjusting device 11. FIG. 2 a shows an enlarged view of axial end 30 and FIG. 2 b shows an exploded view of adjusting device 11. Shaft 22 includes a threaded portion 32, an unthreaded portion 34 coupled to threaded portion 32 and a head portion 36 coupled to unthreaded portion 34. In body 12, unthreaded portion 32 extends through a hollowed portion of shaft 22 and head portion 36 extends into crank 24. Fasteners 40, 42, which may be pins, extending radially through crank 6 into shafts 20, 22, respectively, allow crank 24 to selectively engage either or both of shafts 20, 22. Head portion 36 fits within crank 24 and includes a slot 43 that may be aligned with fastener 42 and that is contoured to receive fastener 42. An end portion 38 of shaft 20 also fits within crank 24 and includes a slot 41 that may be aligned with fastener 40 and that is contoured to receive fastener 40. In order to move plug 18 axially within air bar 10, fastener 42 may be inserted in slot 43 and crank 24 is rotated clockwise to move plug 18 in one axial direction and counterclockwise to move plug 18 in the opposite direction. In order to move plug 16 axially within air bar 10, fastener 40 may be inserted in slot 41 and crank 24 is rotated clockwise to move plug 16 in one axial direction and counterclockwise to move plug 16 in the opposite direction. To move both plugs 16, 18 simultaneously, both fasteners 40, 42 are inserted in respective slots 41, 43 and crank 24 is rotated. After plugs 16, 18 have been positioned as desired, detent lever 26 may engage a flat 44 in crank 24 to prevent crank 24 from rotating and to constrain both shafts 20, 22, thereby preserving the selected setting. Crank 24 is shown as a hand operated device; however, crank 24 may also be a motorized device.

FIGS. 3 and 4 show webs 50, 60 being turned by air bar 10. Holes 100 are shown in body 12 of air bar 10. Holes 100 may be formed on an entire circumference of body 14 or may be only located on a portion of the circumference of body 14. The arrangement of air bar 10 advantageously allows plugs 16, 18 (FIGS. 1 a, 1 b, 1 c) to be adjusted so that air may only pass through holes 100 that are adjacent to passing webs 50, 60. In a preferred embodiment, plugs 16, 18 (FIGS. 1 a, 1 b, 1 c) are adjusted so that cavity 14 (FIGS. 1 a, 1 b, 1 c) is positioned only adjacent to where webs 50, 60 pass air bar 10. As shown in FIG. 3 with web 50, air bar 10 may control air in a symmetric pattern with respect to a longitudinal center of air bar 110. Also, as shown in FIG. 4 with web 60, because plugs 16, 18 may be adjusted independently of one another, air bar 10 may advantageously control air in an asymmetric pattern with respect to longitudinal center 110 of air bar 100.

FIG. 5 a, 5 b, 5 c shows plug 16 according to an embodiment of the present invention. Plug 16 may include a boar 66 for mounting plug 60 on threaded shaft 20 and boars 68, 69 for mounting plug 16 on guide rods that may be included in air bar 10 (FIGS. 1 a, 1 b, 1 c) for axially guiding plug 16. Plug 16 may have a sloped face 65 providing more selectivity in which holes 100 (FIGS. 3 and 4) air passes through. Screws 62, 63, 64 may be located on the end of plug 16.

In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense. 

1. An air bar for guiding a web: a body having holes formed therein; a first plug inside of the body; a second plug inside of the body, the first and second plugs defining a cavity inside of the body; and an adjusting device for selectively moving the first plug and the second plug independently of one another.
 2. The air bar recited in claim 1 wherein the adjusting device is also adapted to selectively move the first plug and the second plug simultaneously.
 3. The air bar recited in claim 1 wherein the adjusting device includes a first shaft coupled to the first plug and a second shaft coupled to the second plug.
 4. The air bar recited in claim 3 wherein the adjusting device further includes a crank coupled to the first and second shafts, the crank being adapted to rotate the first shaft and move the first plug axially within the body and to rotate the second shaft and move the second plug axially within the body.
 5. The air bar recited in claim 4 wherein the adjusting device includes a first fastener for selectively coupling the first shaft to the crank independent of the second shaft.
 6. The air bar recited in claim 5 wherein the adjusting device includes a second fastener for selectively coupling the second shaft to the crank independent of the first shaft.
 7. The air bar recited in claim 3 wherein the first shaft is hollow and a portion of the second shaft passes inside of the first shaft. 